code: def testFFT3D(self):
      self._VerifyFftMethod(
          INNER_DIMS_3D,
          lambda x: x,
          lambda x: np.fft.fftn(x, axes=(-3, -2, -1)),
          signal.fft3d,
          ATOL_3D,
          RTOL_3D,
      )
  
imports: import itertools
  import numpy
  import scipy.signal
  from tensorflow.compiler.tests import xla_test
  from tensorflow.python.framework import dtypes
  from tensorflow.python.ops import array_ops
  from tensorflow.python.ops import gradients_impl
  from tensorflow.python.ops.signal import signal
  from tensorflow.python.platform import googletest
label_desc: Use image node_id 5 for calling the FFTTest obj's underlying member method code with example usage: obj.testFFT3D() without return types